About the time I started kindergarten, a researcher in a laboratory far away picked up a baby rat, handled it briefly, and returned it to the nest. The rat grew up to be resilient to stress, as did its brothers and sisters who were also handled. The effect was traced to changes in the brain's regulation of the body's stress and emotion systems. Thus was born the field of early experiences and stress. Years later, as a research assistant, I pondered why babies cried when uncontrollable toys made loud noises and stumbled into the same field of early experiences and stress. I have spent more than 35 years trying to use our vast knowledge of the neurobiology of stress and development in animals to understand how adverse care during early human development affects physical and mental health. This essay traces my own development as I have sought to understand the human chapter in this mammalian story.